Ukemi in the jujitsu arts is part of the basics. You have to learn how to do it before learning how to throw and be thrown. It's the same as learning the taisabaki (body movement)...i.e. how to enter, retreat keeping the center of balance in the correct position.

One of the important lessons any student can learn is how to control. Whether it is through kata or randori, students have to learn to throw, but not damage their partner, and that's not an easy lesson when it comes to many of the 65 kodokan throws or when hammering someone with a wristlock such as Kotegaishi. When a student learns how "far" they can go with something, then they are learning the art. No on should ever train with someone who doesn't know how to control their technique, I don't care how long they have been training/teaching.